new Function<Long, Long>() {
        @Override
        public Long apply(Long x) {
          return -x;
        }
      };

  private static final Function<BigInteger, BigInteger> NEGATE_BIGINT =
      new Function<BigInteger, BigInteger>() {
        @Override
        public BigInteger apply(BigInteger x) {
          return x.negate();
        }
      };

  /*

      new Function<Long, Long>() {
        @Override
        public Long apply(Long x) {
          return -x;
        }
      };

  private static final Function<BigInteger, BigInteger> NEGATE_BIGINT =
      new Function<BigInteger, BigInteger>() {
        @Override
        public BigInteger apply(BigInteger x) {
          return x.negate();
        }
      };

  /*